Corn meal or grits - Ants cannot completely digest the fiber (cellulose?) in cornmeal and grits. As the indigestible fiber accumulates in the ants' bodies, it blocks nutrient absorption. Eventually, the ants starve. Pour small piles of cornmeal or grits around an area with ants. Your ant population should decline in a week or so.

Vinegar - Ants don't like vinegar (neither do I). Spray a 1 to 1 vinegar and water solution in areas where ants are unwanted. This is a temporary solution, but should give the cornmeal/grits approach time to work.

Boric acid - Boric acid is fairly harmless compound (environmentally speaking) and it kills ants. Pour a circle of boric acid around the cornmeal/grits piles; this ensures that ants will crawl through the boric acid on their way to the food.

Boiling water - Pour boiling water over and into nest. Should kill ants on contact.

Maple Syrup - Yes, put a small bottle of some sweet stuff (maple syrup, corn syrup) near the ant nest. It should feed them all summer so they won't have to venture into your house for food or water.